Nope, if it happens with games, and the early start-up screen (your best indication as no preferences can be applied at that stage) it's a problem with one of the RGB components, in this case, green. To be sure, open an image containing something you know to be green, and it should appear very dark, pure green being shown as black. When green's missing from a neutral colour such as white or grey, the result will always be pink as they are complimentary colours.
If you have the schematics, try tracing the green line back as far as you can and check for breaks in tracks etc., especially around chip connections, but without an oscilliscope your fairly limited as to how far you can test the video circuits. With a bit of luck there'll be a broken or shorted track somewhere on the green circuit, and rectifying this will fix it... If you're unlucky, you'll need to replace some parts - not a nice job on a 600 I'm afraid...
